function Ft = Ft_Cali(imu, avp, eth, dwb, ts)

nn = size(imu,1);
wb = mean(imu(:,1:3))'./ts;      % rad -> rad/s
fb = mean(imu(:,4:6))'./ts;      % m/s -> m/s^2
Cnb = a2mat(avp(1:3));

F11 = -CrossMat(eth.wnie);
F13 = -Cnb*[wb(1)*eye(3) wb(2)*eye(3) wb(3)*eye(3) eye(3)];
F21 = CrossMat(Cnb*fb);
F22 = -CrossMat(2*eth.wnie);
F24 = Cnb*[fb(1)*eye(3) [0 0; fb(2)*eye(2)] [0; 0; fb(3)] eye(3)];
F25 = Cnb*(diag((fb./eth.g).^2)).*1e-6.*eth.g;
W = (CrossMat(wb)*CrossMat(wb) + CrossMat(dwb));
F26 = Cnb*[W(1,:); zeros(2,3)];
F27 = Cnb*[zeros(1,3); W(2,:); zeros(1,3)];
O33 = zeros(3,3); O39 = zeros(3,9); O312 = zeros(3,12);
O30 = zeros(30,36);
Ft = [ F11 O33 F13  O39 O33 O33 O33
       F21 F22 O312 F24 F25 F26 F27
                  O30                 ];

end

